JPS6188264A - Photoconductive film and electrophotographic sensitive body using said film - Google Patents

Abstract

PURPOSE:To attain high sensitivity by incorporating a specified tropylium salt compound. CONSTITUTION:A photosensitive layer contg. the tropylium salt compound represented by the formula (where each of R1-R6 is alkyl, aralkyl or aryl; two adjacent groups selected from R1-R6 may be residues forming a condensed ring contg. a tropylium ring; R7 is an aromatic hydrocarbon group or a heterocyclic group; A<-> is an anion; and n=0, 1 or 2) is formed. It is preferable that he photosensitive layer is of separated function type, and the tropylium salt compound is used in the charge generating layer. The amount of the tropylium salt compound in the charge generating layer is made as large as possible so as to attain satisfactory absorbance, and the charge generating layer is made this so as to shorten the trajectory of generated charge carriers. A panchromatic electrophotographic sensitive body having high sensitivity can be obtd. by using the tropylium salt compound combined optionally with other photoconductive pigment or dye which is different from the tropylium salt compound in light absorption. The sensitive body is used in not only a copying machine but also a laser beam printer or an LED printer.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a novel photofour-electroconductive coating and a highly sensitive electrophotographic photoreceptor using the same.

BACKGROUND ART Conventionally, pigments and dyes exhibiting photoconductivity have been published in numerous publications.

For example, “ROA Review” VOl, 23.
P, 413-F, 419 (1962, 9), the photoconductivity of 7-thalocyanine pigments was announced, and electrophotographic photoreceptors using this 7-thalocyanine pigment were published in U.S. Pat. No. 5,597,086 and U.S. Pat. No. 3816
This is shown in Publication No. 118, etc. In addition, examples of organic semiconductors used in electrophotographic photoreceptors include, for example, U.S. Pat.
315983, U.S. Patent No. 4327169 and "Re5each Disclosure'2051"
7 (1981, 5), pyrylium dyes,
Examples include squaric acid methine dyes shown in US Pat. No. 3,824,099, and disazo pigments shown in US Pat. No. 3,898,084 and US Pat. No. 4,251,613.

Such organic semiconductors are easier to synthesize than inorganic semiconductors, and can be synthesized as compounds that have photoconductivity for light in the required wavelength range. An electrophotographic photoreceptor formed on a conductive support has the advantage of improved color sensitivity, but only a few of them are practical in terms of sensitivity and durability.

Problems to be Solved by the Invention A first object of the present invention is to provide a highly sensitive photoconductive coating.

A second object of the present invention is to provide an electrophotographic photoreceptor using a highly sensitive photoconductive coating.

A third object of the present invention is to provide an electrophotographic photoreceptor suitable for electrophotographic copying machines.

Means and Effects for Solving the Problems The objects of the present invention are achieved by using a tropylium salt compound represented by the following general formula (I).

That is, the present invention comprises an electrophotographic photoreceptor characterized by being provided with a photoconductive coating containing a tropylium salt compound represented by the following general formula (1) and a photosensitive layer having the coating.

In the general formula, n represents an integer selected from 0.1.2, and R1 to R6
is an alkyl group such as methyl, ethyl, propyl, an aralkyl group such as benzyl or phenethyl, or an aryl group such as phenyl or naphthyl. , alkoxy groups such as methoxy, ethoxy, propoxy, dimethylamine,
diethylamino, diphenylamino, benzylamino,
Morpholino and pyro may be substituted with a substituted amino group such as lysine or pyrrolidino, or a hydroxyl group.

Further, two adjacent groups selected from R1 to R6 represent a residue that forms a condensed ring with the tropylium ring.

R7 is an aromatic hydrocarbon group derived from benzene, naphthalene, -thracene, helene, fluorene, etc., which may have a substituent, or phenothiazine, phenoxazine, carbazole, indole, hyrol, 7ran, thiophene, dibenzofuran , represents a heterocyclic group derived from acridine, etc.

Substituents for aromatic hydrocarbon groups and heterocyclic groups include lower alkyl groups such as methyl, ethyl, propyl, and butyl, alkoxy groups such as methoxy, ethoxy, propoxy, and butoxy, aryloxy groups such as phenoxy, and methyl mercaft. , an alkylmercapto group such as ethylmercapto, an amino group, a dialkylamino group such as dimethylamino, diethylamino, dipropylamino, dibutyami 7, etc., a dialkylamino group such as :) benzylamino, a diarylamino group such as diphenylamino, methylphenyl amino,
Ethylphenylamino, cyanoethylphenylamino,
Alkylaryl amino groups such as chloroethylphenylamino, benzylmethylamino, benzylethylamino,
Alkylarkylamino groups such as benzylcyanoethylamino, 7-ralkylarylamino groups such as benzylphenylamino, cyclic amino groups such as piperidino, morpholino, pyrrolidino, β-arylethylene groups such as p-dimethylaminostyryl, p-dimethylamino Examples include arylazo groups such as phenylazo groups, heloquine atoms such as chlorine, bromine, and iodine.

A″″ represents an anion group, and specific examples include knee, total, and
1cn-1cj! 04-1BF4-1PF6-s H2
O (Oki 03-0HsBOs', 02H5SO4-1OH
Anions such as sSO4- are included.

Next, a general method for producing the tropylium salt compound used in the present invention will be described.

The compound represented by general formula (1) is or reaction formula (2) is synthesized according to

The symbols in reaction formulas (1) and (2) have the same meanings as those in general formula (I).

Literature regarding the synthesis method includes ahθmBer, u
29-48 (1964), Chem Ber, 111
590-1598 (1964) K is described.

Specific examples of the tropylium salt compounds used in the present invention are listed below.

Compound jtun-IQ The coating containing the above-mentioned tropylium salt compound exhibits photoconductivity, and therefore can be used in the photosensitive layer of the electrophotographic photoreceptor described below.

That is, in the specific example of the present invention, f)1 is formed by forming a film of the above-mentioned tropylium salt compound on a conductive support by vacuum evaporation, or by incorporating a fraction of it in an appropriate binder to form a film. A child photographic photoreceptor can be prepared.

In a preferred embodiment of the present invention, the photosensitive layer fnear1J of the electrophotographic photoreceptor is functionally separated into a charge generation layer and a charge transport layer, and the photosensitive layer is used as the charge generation layer in the fc photoreceptor IC2. Can be applied.

The charge generation layer contains as much of the above-described photoconductive compound as possible in order to obtain sufficient absorbance, and a thin film layer to shorten the range of the generated charge carriers.
For example, it is preferable to use a thin film layer having a thickness of 5μ or less, preferably α01 to 1μ. This means that most of the incident light is absorbed by the charge generation layer, generating many charge carriers, and that the generated charge carriers are not deactivated by recombination or trapping, but are transferred to the charge transport layer. This is due to the need for injection.

The charge generation layer can be formed by dispersing the above-mentioned compound in a suitable binder and coating it on the substrate, or can be obtained by forming a vapor deposited film using a vacuum vapor deposition apparatus. The binder that can be used to form the charge generating layer by coating can be selected from a wide variety of insulating resins, and can also be selected from organic photoconductive polymers such as boy-H-vinylcarbazole, polyvinylanthracene, and polyvinylpyrene.

Preferably, polyvinyl protein, polyarylate (condensation polymer of bisphenol A and 7-talic acid, etc.)
Polycarbonate, polyester, phenoki 7 resin, polyvinyl acetate, acrylic resin, polyacrylamide,
polyamide, polyvinylpyridine, cellulose resin,
All insulating resins such as urethane 4if resin, epoxy resin, camoin, polyvinyl alcohol, and polyvinylpyrrolidone can be mentioned. The resin contained in the charge generation layer is suitably 80% by weight or less, preferably 40% by weight or less.

The solvent that dissolves these resins varies depending on the type of resin, and is preferably selected from those that do not dissolve the charge transport layer or undercoat layer described below. Specific solvents include alcohols such as methanol, ethanol, and isopropanol, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, amides such as N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl. Sulfoxides such as sulfoxide, tetrahydrofuran, dioxane.

Ethers such as ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, chloroform, methylene chloride, dichloroethylene, tetral1m carbon i, ) +7 Aliphatics such as chlorethylene 71
Zero-genated hydrocarbons or aromatic compounds such as (benzene, toluene, xinane, ')IOyne, monochlorobenzene, dichlorobenzene, etc. can be used.

Coating methods include dip coating, spray coating, spinner coating, bead coating,
This can be carried out using a coating method such as a Mayer bar coating method, a blade coating method, a roller coating method, or a curtain coating method. For drying, it is preferable to dry to the touch at room temperature and then heat dry. Heat drying can be carried out at a temperature of 30 to 200° C. for a period of time ranging from 5 minutes to 2 hours, either stationary or under ventilation.

The charge transport layer is electrically connected to the charge generation layer described above, and receives and takes charge carriers injected from the charge generation layer in the presence of an electric field.

It has the function of transporting these charge carriers to the surface. At this time, this charge transport layer may be laminated on or under the charge generation layer. However, if the charge generation layer is the uppermost layer, the coating may be scratched during repeated use, causing a change in sensitivity, so it is preferable that the charge transport layer is stacked on top of the charge generation layer.

The substance that transports charge carriers in the charge transport layer (hereinafter simply referred to as charge transport substance) is preferably substantially insensitive to the wavelength range of electromagnetic waves to which the charge generation layer is sensitive. The term "electromagnetic waves" used herein includes a broad definition of "light rays" including r-rays, X-rays, ultraviolet rays, visible light, near-infrared rays, infrared rays, far-infrared rays, and the like. When the photosensitive wavelength range of the charge transport layer coincides with or overlaps that of the charge generation layer, charge carriers generated in both layers trap each other, resulting in a decrease in sensitivity.

Charge-transporting substances include electron-transporting substances and hole-transporting substances; examples of electron-transporting substances include chloranil, furoanil, tetrac gamma ethylene, tetracyanoquinodimethane, 2,4,7-dolinitro-9-fluorenone,
2,4,5.7-tetranitro-9-fluorenone, 2
, 4.7-) Dinitro-9-dicyanomethylene fluorenone, 2.4,5.7-teto-2-nitrochitington, 2
, 4,8-trinidrothioxanthone and other electron-withdrawing substances, and polymerized products of these electron-withdrawing substances.

Examples of hole transporting substances include pyrene, N-ethylcarbazole, N-isopropylcarbazole, N-methyl-N
-phenylhydrazino-3-methylidene-9-ethylcarbazole, N,N-diphenylhydrazino-3-methylidene-9-ethylruhasol, N,N-u phenylhydrazino-3-methylidene-10-ethylphenothiazine, N,N-diphenylhydrazino-3-methylidene-10-ethylphenoxazine, P-diethylaminobenzaldehyde N,N-diphenylhydrazino,
P->ethylaminobenzaldehyde N-α-su7thi-N-7dynylhydrazone, P-pyrrolidinobenzaldehyde N, N-diphenylhydrazone, 1,3.3
-) Dimethylindolenine-ω-aldehyde-N,N
-di72nihydrazone, p-diethylbenzaldehyde-3-methylbenzthiazolinone-2-hydrazones, 2,5-bis(p-uethylaminophenyl)-1,3,4-oxadi Azole, 1-phenyl-5-(p-diethylaminostyryl)-5-(P
-diethylaminophenyl)pyrazoline, 1-(quinolyl(2):l-3-(P-diethylaminostyryl)
-5-(P-diethylaminophenyl)bicizoline, 1
-[Pyridyl (2)) -3-(P-diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline, 1-(6-medox-7-pyridyl (2)) -3-,
(P-diethylaminosutiJ/')-5-(p-diethylaminophenyl)pyrazoline, 1-[pyridyl (3)
) -3-(p-diethylaminostyryl)-5-
(P-diethylaminophenyl)pyrazoline, 1-[lepidyl (2):l-3-(P-diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline,
1-[pyridyl(2))-3-(P-diethylaminosteryl)-4-methyl-5-(P-diethylaminophenyl)bicizoline, 1-[pyridyl(2>)-3-
(α-Methyl-P-diethylaminostyryl)-5-(
P-diethylaminophenyl)bicizoline, 1-phenyl-3-(p-diethylaminosteryl)-4-methyl-5-(P-uethylaminophenyl)pyrazoline, 1
-Phenyl-3-(α-benzyl-P-diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline, spiropyrazoline and other pyrazolines, 2-(
P-diethylaminostyryl)-6-dinithylaminobenzoxasol, 2-(P-diethylaminophenyl)-4-(P-dimethylaminophenyl)-5-(2-
Oxazole compounds such as chlorophenyl)oxazole, thiazole compounds such as 2-(P-diethylaminostyryl)-6-dinithylaminobenzotheazole, bis(4-:)ethylamino-2-methylphenyl)-phenylmethane, etc. triarylmethane compound, 1.1
-bis(4-N,N-diethylamine-2-methylphenyl)butane, 1,1,2,2-tetrakis(4-N
, N-dimethylamino-2-methyl7enyl)ethane and other polyarylalkanes, triphenylamine, poly-N-vinylcarbazole, polyvinylpyrene, polyvinyanthracene, polyvinylacridine, poly-9-
Examples include vinylphenylanthracene, helene-formaldehyde resin, and ethylcarbazole formaldehyde resin.

In addition to these organic charge transport materials, inorganic materials such as selenium, selenium-tellurium amorphous silicon, and cadmium i-ide can also be used.

Further, these charge transport substances can be used alone or in combination of two or more.

When the charge transport material does not have film-forming properties, a film can be formed by selecting an appropriate binder. Examples of resins that can be used as binders include acrylic resin,
polyarylate, polyester, polycarbonate, polystyrene, acrylonitrile-styrene copolymer,
Insulating resins such as acrylonitrile-butadiene copolymer, polyvinyl butyral, polyvinyl formal, polysulfone, polyacrylamide, polyamide, chlorinated rubber, or organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, polyvinylpyrene, etc. be able to.

Since the charge transport layer has a limit in its ability to transport charge carriers, it cannot be made thicker than necessary. Generally, it is 5 to 30μ, but the preferred range is 8 to 20μ.
It is. When forming the charge transport layer by coating, an appropriate coating method as described above can be used.

A photosensitive layer consisting of such a stacked structure of a charge generation layer and a charge transport layer is provided on a substrate having a conductive layer. As the substrate having a conductive layer, the substrate itself has tetraconductivity,
For example, aluminum, aluminum alloy, copper, zinc, stainless steel, vanadium, molybdenum, chromium, titanium,
In addition to using materials such as nickel, indium, gold, and platinum, aluminum, aluminum alloys, indium oxide, tin oxide, and indium oxide-tin oxide alloys are used to form a film using a vacuum deposition method. For example, polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, acrylic resin,
conductive particles (e.g., carbon black, silver particles, etc.), substrates coated on plastic with a suitable binder, substrates in which plastic or paper is impregnated with conductive particles, or tetraconductive polymers? It is possible to use plastics that have

An undercoat layer having a barrier function and an adhesive function can also be provided between the 4-electroconductor layer and the photosensitive layer. The subbing layer is casein,
Polyvinyl alcohol, nitrocellulose, ethylene-
Acrylic acid copolymer, polyamide (nylon 6, nylon 66, nylon 610, copolymerized nylon, alkoxymethylated nylon, etc.), polyurethane, upper 2-tin,
It can be formed from aluminum oxide, etc.

The thickness of the subbing layer is 0.1 to 5μ, preferably a5 to 3μ.
is appropriate.

When using a photoreceptor in which a conductive layer is laminated in the order of a charge generation layer and a charge transport layer, and the charge transport material is an electron transport material, the surface of the charge transport layer must be positively charged, and after charging When exposed to light, electrons generated in the charge generation layer are injected into the charge transport layer in the exposed area, and then reach the surface and neutralize the positive charge, resulting in attenuation of the surface potential and an electrostatic contrast between it and the unexposed area. arise.

A visible image can be obtained by developing the electrostatic latent image thus formed with a negatively charged toner. Either fix this directly, or transfer the toner image to paper or plastic film, etc.
When developed and fixed, a black color appears.

Alternatively, a method may be used in which the electrostatic latent image on the photoreceptor is transferred onto an insulating layer, which is not transferred, and then developed and fixed. The type d developer, developing method, and fixing method may be any known ones or known methods, and are not limited to specific ones.

On the other hand, when the charge transport material consists of a hole transport material, it is necessary to charge the surface of the charge transport layer negatively, and after charging, when exposed to light, the holes generated in the charge generation l' in the exposed area are transferred to the charge transport layer. It is injected and then reaches the surface to neutralize the negative charges, resulting in attenuation of the surface potential and an electrostatic contrast between it and the unexposed area. At the time of development, it is necessary to use a toner that is positively loaded, contrary to the case where an electron-transporting substance is used.

Furthermore, it is also possible to form a single-layer type photoreceptor in which a tropylium salt compound is dispersed in the binder resin.

Further, in another specific example of the present invention, the above-mentioned human 2 sins,
Organic photoconductive substances such as pyrazolines, oxazoles, thiazoles, triarylmethanes, polyarylalkanes, triphenylamine, and poly-N-vinylcarbazoles, and inorganic photoconductive substances such as zinc oxide, cadmium sulfide, and selenium. It is also possible to form a photosensitive film containing the above-mentioned tropylium salt compound as a sensitizer. This photosensitive film is formed by coating these photoconductive substances and the above-mentioned tropylium salt compound together with a binder.

Further, as another specific example of the present invention, Japanese Patent Application Laid-Open No. 49-9164
It is also possible to disperse a charge generating material in a charge transfer complex as disclosed in Publication No. 8 (Photoconductive Member) and use it as a Type 9 photoreceptor.

All photoreceptors contain at least one kind of tropylium salt compound selected from the compounds represented by the general formula (I), and are used in combination with other photoconductive pigments or dyes with different light absorption depending on the required KC. By doing so, it is possible to increase the sensitivity of this photoreceptor or to prepare it as a panchromatic photoreceptor.

The electronic device X photoreceptor of the present invention can be used not only in electrophotographic copying machines, but also in laser beam printers, LED printers, C! It can also be widely used in the application field of playback photography such as RT printers.

Hereinafter, the present invention will be explained according to examples.

Examples 1 to 12 Ammonia aqueous solution of casein (casein 1
1. 28% ammonia water iF, water 222 m) was applied using a Mayer Parr so that the film thickness after drying was 1.0 μm, and dried.

Next, butyral resin (butyralization degree 63 mol%) 2
To a solution dissolved in 95% of r't inpropyl alcohol, each of the 12 tropylium salt compounds 51 listed in the table below was added to prepare a 12-pound coating solution.

After dispersing each coating solution in a sand mill for 6 hours + gJ, the film thickness after drying was 0.1μ on the casein undercoat layer.
It was coated with a Mayer Per and dried to form a charge generation layer.

Next, the hydrazone compound of structural formula 5? and polymethyl methacrylate resin (number average molecular weight 100, ooo) were dissolved in 70rnt of benzene, and this was applied onto the charge generation layer using a Mayer par so that the dry film thickness was 12μ, and dried. 12 created by forming a lever carrying cypress noah and making nine shapes.
A type of photoreceptor was statically charged with corona at 15 KV using an electrostatic copying paper tester MO modified eISP-428 manufactured by Kawaguchi Electric Co., Ltd., and held in a dark place for 1 second.
It was exposed to light for 4 seconds at an illuminance of 51 ux, and the charging characteristics were examined.

The charging characteristics include the initial charging potential (Vo) and the amount of light exposure (E) required to attenuate the potential after 1 second of dark decay to A.
3() was measured. The results are shown in the first garment. Also, 20
The residual potential after 1+ux-sec 4 light was expressed in VR.

Table 1 Example 13 Polyester resin (manufactured by Toyobo Co., Ltd., Byron 200) 5
f and 1-[pyridyl-(2))-3-(4-N, M
-diethylaminostyryl)-5-(4-N,N-diethylaminophenyl 1%/)pyrazoline 51 was dissolved in 80 ml of methyl ethyl ketone, and the above-mentioned tropylium compound 91NCL1 was added with a total of 1.0 P. After dispersion, aluminum was deposited. Coated on polyester film and dried.
A photoreceptor having a photosensitive layer with a dry film thickness of 13 μm was prepared.

The characteristics of this photoreceptor were measured by the same method as in Example 1, including the initial charging potential (Vo) and the exposure amount (8%) required to attenuate the charging potential to H after 1 second of dark decay. I got on the train as shown below. (However, the charging polarity was set as ■.

) VO: +583V E3A: 4.01uxΦsec Example 14 PoIJ + N-vinylcarbazole 1? and the aforementioned tropylium salt compound No.95 were mixed with 1,2-dichloroethane 1
After adding it to 02, it was thoroughly stirred.

The coating solution prepared in this way was coated on a polyethylene terephthalate film coated with aluminum to give a dry film thickness of 15%.
It was applied with a doctor blade so that it was μ.

The charging characteristics of this photoreceptor were measured in the same manner as in Example 1. However, the charging polarity was O. The results are shown below.

Vo: ÷580v K3A: 4.1lux-aec Example 15 Shinko of the above-mentioned Example 5-14, +, = 1:; Light body tko, Hatake 3
Tropylium/gold chloride i used when making clay; 7) N11
In place of 9, the above tropylium salt compound +f! IL 13
After preparing a photoreceptor using exactly the same method as in Example 14, the charging characteristics of this photoreceptor were measured. The results are shown below. However, Obi'QQ jade is marked as ■.

v□ 2 +570v KH: 3.7 lux@sec Example 16 Fine particle C zinc uride (5azex 2000 manufactured by Sakai Kagaku ■)
)10? , an acrylic carrier (Mitsubishi Rayon Rayon LROO9) 4F, toluene 102, and the above-mentioned tropylium salt compound 1 were thoroughly mixed in a 10rnqe ball mill, and the resulting coating solution was subjected to aluminum evaporation. The film was coated onto the polyethylene terephthalate film prepared using a doctor blade to a dry film thickness of 21 μm, and dried to prepare an electrophotographic photoreceptor.

When the spectral sensitivity of this electrophotographic photoreceptor was measured using spectrophotography using electrophotography, it was found that the photoreceptor of this example had a ruptured film on the longer wavelength side, compared to the zinc oxide film that did not contain the tropylium salt compound described above. It was found that it has sensitivity.

Example 17 A polyvinyl alcohol film having a thickness of 1.1 μm was formed on the aluminum surface of an aluminum vapor-deposited polyethylene terephthalate film.

Next, a coating solution containing the same tropylium salt compound as in Example 6 was applied onto the previously formed polyvinyl alcohol layer.
It was coated with a Mayer bar so that the film thickness after drying was 0.1 μm, and dried to form a charge generation layer.

Next, pyrazoline compound 52 of the structural formula and polyarylate resin (condensation polymer of bisphenol A and terephthalic acid-isophthalic acid)
A solution obtained by dissolving 5f in 70 TntK of tetrahydrofuran was applied onto the charge generation layer so that the film thickness after drying was 10 μm, and dried to form a charge transport layer.

The charging characteristics of the photoreceptor thus prepared were measured in the same manner as in the examples. The results are shown below.

To: -600V E3A: 2.91ux・sec Example 18 An ammonia aqueous solution of casein was applied on a 100μ thick aluminum plate, dried and Il? A subbing layer having a thickness of 1.1 μm was formed.

Next, 2,4.7-dolinitro9-fluorenone 5? and poly-N-vinylcarbazole (number average molecule, amount 300,000) 5F were dissolved in 70% of tetrahydrofuran to form a charge transfer complex. This charge transfer complex compound and 1 m8 11 of the above-mentioned tropylium salt compound were added to a solution in which 5 t of polyester resin (manufactured by Byronni Toyobo) was dissolved in 70 ml of tetrahydro 7 run, and dispersed. This dispersion was applied onto the undercoat layer so that the film thickness after drying was 12 μm, and dried. The charging characteristics of the photoreceptor thus prepared were measured in the same manner as in Example 1. These results were as follows.

However, the charging polarity was set to ■.

Vo: +560V

Claims (3)

[Claims] (1) A photoconductive film containing a tropylium salt compound represented by the following general formula (I). ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) In the formula, n represents an integer selected from 0, 1, and 2, and R_1 to R_6 are an alkyl group, an aralkyl group, an aryl group, or a group selected from R_1 to R_6. Two adjacent groups represent a residue forming a condensed ring with the tropylium ring, R_7 represents an aromatic hydrocarbon group or a heterocyclic group which may have a substituent, and A^- represents an anion group. shows. (2) An electrophotographic photoreceptor characterized in that a photosensitive layer having a photoconductive film containing a tropylium salt compound represented by the following general formula (I) is provided on a conductive support. General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) In the formula, n represents an integer selected from 0, 1, and 2, and R_1 to R_6 are alkyl groups, aralkyl groups, aryl groups, or R_1 to R_6. Two selected adjacent groups represent residues that form a condensed ring with the tropylium salt, R_7 represents an aromatic hydrocarbon group or a heterocyclic group which may have a substituent, and A^- represents Indicates an anion group. (3) The photosensitive layer provided on the conductive support is a charge generation layer having at least a photoconductive coating containing a tropylium salt compound represented by the general formula (I) as set forth in claim 2. The electrophotographic photoreceptor according to claim (2), wherein charge transport layers are sequentially laminated.